This invention relates to a method and apparatus for determining cleave end angle of an optical fiber.
Quality control is very important in manufacture of optical fiber. Factors that have a bearing on quality of an optical fiber include the roundness of the fiber, the size of the fiber and whether the core is centered within the cladding.
Roundness, diameter and centering may be determined by examining an end face of the fiber. However, if the end face of the fiber is not perpendicular to the longitudinal axis of the fiber, the accuracy of the measurements of roundness, diameter and centering may be impaired. Therefore, it is desirable to measure the angle between the end face of the fiber and a plane perpendicular to the longitudinal axis of the fiber (the cleave and angle) before carrying out other measurements, and to recleave the fiber and provide another end face if the angle is not sufficiently close to 90.degree.. One method of measuring the cleave end angle of an optical fiber involves use of a Mach-Zehnder interferometer, which is not otherwise used in determining roundness, diameter and centering. It is expensive and inconvenient to have to employ a dedicated machine for measuring cleave end angle.